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Biomedical subjects

H Koga

Publications and source records attributed to H Koga.

At least 163 records · Page 9Linked to original sources

Jejunal angiodysplasia confirmed by intravascular injection technique in vitro. Report of a case and review of the literature.

Angiodysplasia of the small intestine is a rare but important cause of gastrointestinal bleeding. We present a 64-year-old man with repeated melena in whom the diagnosis of multiple angiodysplasia of the jejunum was suggested by angiography. The affected segment of the small intestine, in which reddish patches were detected by intraoperative endoscopy, was removed. The combined technique of injecting a dye and a water-soluble contrast medium into the resected specimen revealed areas of dilated vessels, which were diagnosed histologically as angiodysplasia. This case suggests that angiodysplasia of the small intestine can be recognized clinically before the operation and that the intravascular injection technique is useful in confirming the diagnosis in the resected specimen in vitro. We describe this case in detail and review other cases of small intestinal angiodysplasia reported in the English literature.

Angiodysplasia↗

A comparative study of glioma cell lines for p16, p15, p53 and p21 gene alterations.

A total of 10 glioma cell lines were examined for alterations of the p16, p15, p53 and p21 genes, which are tumor suppressor genes or candidates with direct or indirect CDK-inhibitory functions. Genetic alterations (deletions or mutations) were frequently seen in the p16, p15 and p53 genes in these cell lines, but not in the p21 gene. When the states of the p16, p15 and p53 genes were compared among cell lines, all the cell lines showed abnormalities in at least 1 gene, often in 2 or 3 genes coincidentally, suggesting that dysfunction of these genes is closely related to glioma cell growth. Although alteration of all 3 genes was most frequent, there were cell lines having either p16/p15 or p53 or pl6 and p53 gene alterations, suggesting that the time order of these genetic alterations was variable depending on the cell line. Among cell lines examined, one with homozygous p53 gene deletion seemed of particular practical value, since such a cell line might be useful in various studies, including investigation of the functions of various mutant p53 genes in the absence of heteromeric protein formation. On examination of the primary tumor tissues, the same alterations of the p16/p15 and p53 genes as detected in the cell lines were demonstrated in all 6 cases examined: p16/p15 gene deletion in 1, p16 gene mutation in 1 and p53 gene mutations in 5 cases. This suggested that the p16/p15 and the p53 gene alterations and their combinations in at least some glioma cell lines reflected those in the primary glioma tissues.

Adult↗

Hyperbaric oxygenation prevents delayed neuronal death following transient ischaemia in the gerbil hippocampus.

The mechanism of the neuroprotective effect of hyperbaric oxygenation remains unclear although its clinical benefits have been well recognized for human ischaemic neuronal disease. The preventive effect of hyperbaric oxygenation against delayed neuronal death was investigated in the gerbil following transient forebrain ischaemia. Delayed neuronal death in the gerbil was produced by clips on both the common carotid arteries (10 min). Morphological examination was carried out after several protocols of hyperbaric oxygenation, modified from the protocols for human ischaemic neuronal disease. Neurons in the hippocampal CA1 were well preserved in the gerbils treated with hyperbaric oxygenation, more so than in the gerbils with no hyperbaric oxygenation. Moreover, more neurons were preserved in the CA1 treated with hyperbaric oxygenation within 6 h of the ischaemia, than when the hyperbaric oxygenation was started 24 h after the ischaemia. The induction of heat shock proteins (HSP72 and HSP27) became weaker in the gerbils with hyperbaric oxygenation than in those without hyperbaric oxygenation, as seen immunohistochemically. We also observed an increase in dense bodies, that were shown to be lysosomes and myelinoid structures in the cytoplasm of the neurons ultrastructurally, in the hippocampus with hyperbaric oxygenation. However, no oxygen toxicity to the neurons was detected, up to at least two atmospheres absolute. This experimental system was useful to investigate the preventive mechanism of hyperbaric oxygenation against delayed neuronal death in the gerbil, and to determine the clinical indications and the most effective protocol for hyperbaric oxygenation for ischaemic neuronal damage in the human brain.

Animals↗

Cumulative renal damage in dogs by repeated treatment with extracorporeal shock waves.

BACKGROUND: Extracorporeal shock wave lithotripsy (ESWL) has become a routine method for the treatment of renal and ureteral calculi. Occasionally, multisequential ESWL treatments and high energy shock waves are required to treat large calculi. The purpose of the study was to compare renal histopathologic damage caused by varying the application of shock waves. METHODS: Six groups of dogs were defined by the frequency of shocks, application time and numbers of sessions. Bilateral nephrectomies were performed immediately, 3, 7 and 60 days after the application of shock waves. Histopathologic features of the kidneys were assessed by both light and electron microscopy. RESULTS: Irreversible damage was observed in all exposed kidneys. After a single session of low application frequency, damage by shock waves occurred with progressive deterioration of the nephron. At any frequency rate, the damage was caused by tissue hypoxia due to rupturing of the interstitial capillaries. As the application frequency increased, capillary rupture became more severe, and consequently, morphological damage tended to be more intense. Repeated sessions at any application frequency made the damage more intense, suggesting that an accumulation of damage had occurred. CONCLUSIONS: Minimal doses of shock waves cause renal damage and repeated ESWL sessions may result in an accumulation of damage. Considering that the damage is dose-dependent, divided ESWL treatments at a low frequency rate are advisable in a clinical setting.

Animals↗

[Invasive pulmonary aspergillosis caused by aspiration of polluted water after nearly drowning].

A 21-year-old male nearly drowned in a reservoir by a traffic accident and he aspirated a large mount of polluted water containing Aspergillus fumigatus. On admission to our hospital, he was alert but cyanotic. Chest rentogenograms showed scatter infiltrative shadows in bilateral lung fields. We administered methylpredonizolon and antimicrobial agents immediately because of respiratory failure which was rapidly progressing. During the following six days, infiltrative shadows diminished but multiple nodular shadows in both lung fields appeared. The diagnosis of pulmonary aspergillosis was confirmed by serological and microbiological studies. Intravenous amphotericin B and oral itraconazol were administrated, and clinical improvement was observed.

Adult↗

[Two cases of pulmonary dirofilariasis in Nagasaki Prefecture].

We reported two cases of pulmonary dirofilariasis in Nagasaki Prefecture. Each case was admitted to our hospitals for evaluation of an abnormal shadow on chest X-ray film taken for examination. We strongly suspected lung cancer before operation. It was resected in order to confirm the pathological diagnosis. There was a Dirofilaria immitis in the vessels surrounded by the necrotic tissues. The case of pulmonary dirofilariasis tends to increase in Japan, but the positive rate of dogs with Dirofilaria immitis tends to decrease, because of decreasing breeding places of mosquitoes by the spread of the public sewage system in Nagasaki City.

Adult↗

Evaluation of susceptibility of gram-positive and -negative bacteria to human defensins by using radial diffusion assay.

Defensins are small cationic bactericidal peptides present abundantly in the granules of polymorphonuclear neutrophils (PMNs). Human PMNs contain four defensins termed HNP-1 to HNP-4. We used a new assay system in agar plates, the radial diffusion assay, to evaluate the effects of human defensins against gram-positive and -negative bacteria. A crude mixture of HNP-1, -2, and -3 (crude HNPs) was purified from human PMN extracts by reversed-phase high-pressure liquid chromatography (RP-HPLC). The different components were later separated by RP-HPLC and gel permeation chromatography. We compared the antibacterial activities of purified HNP-1, -2, and -3 against Escherichia coli, Pseudomonas aeruginosa, methicillin-susceptible Staphylococcus aureus, and methicillin-resistant S. aureus strains using the radial diffusion assay. The antibacterial activities of HNP-1 and HNP-2 against all strains tested were similar to those of the crude HNPs, but the activity of HNP-3 was less than those of the other defensins. To quantitate the activities of HNPs against different bacteria, we defined the minimal dose of crude HNPs forming a detectable clear zone around the bacteria as the minimal inhibitory dose (MID) and determined the MIDs for 10 strains of E. coli, 12 strains of P. aeruginosa, 10 strains of methicillin-susceptible S. aureus, and 12 strains of methicillin-resistant S. aureus isolates, including clinical isolates. In general, the MIDs of the HNPs were similar against similar bacterial species. However, the MIDs for P. aeruginosa were higher than those for the other organisms tested. The radial diffusion assay is suitable as a screening test for measuring the susceptibilities of isolates to defensins, because it is sensitive and simple and has good reproducibility.

Anti-Bacterial Agents↗

Relationship between rifampin MICs for and rpoB mutations of Mycobacterium tuberculosis strains isolated in Japan.

We analyzed the relationship between rifampin MICs and rpoB mutations of 40 clinical isolates of Mycobacterium tuberculosis. A point mutation in either codon 516, 526, or 531 was found in 13 strains requiring MICs of > or = 64 micrograms/ml, while 21 strains requiring MICs of < or = 1 microgram/ml showed no alteration in these codons. However, 3 of these 21 strains contained a point mutation in either codon 515 or 533. Of the other six strains requiring MICs between 2 and 32 micrograms/ml, three contained a point mutation in codon 516 or 526, while no alteration was detected in the other three. Our results indicate that the sequencing analysis of a 69-bp fragment in the rpoB gene is useful in predicting rifampin-resistant phenotypes.

Amino Acid Sequence↗

New drug susceptibility test for Mycobacterium tuberculosis using the hybridization protection assay.

We developed a novel method for early detection of drug-resistant strains of Mycobacterium tuberculosis by using the hybridization protection assay (HPA). The number of viable bacteria during the incubation period correlated well with the number of relative light units measured by the HPA. In addition, the relative light unit values of susceptible strains on the first, third and fifth days of incubation were significantly different from those of resistant strains for both isoniazid and rifampin. Our results suggest that after isolation of the organism from clinical specimens, drug-resistant strains of M. tuberculosis are accurately detected by the HPA even after 1 day of incubation with the drug.

Antibiotics, Antitubercular↗

[Clinical review of 105 cases of adrenal tumor, with special reference to incidental tumor].

We reviewed 105 patients with adrenal tumor diagnosed at our institute from January 1984 to December 1993. In 74 patients tumors were symptomatically diagnosed (the symptomatic group), while in the remaining 31 patients tumors were incidentally detected (the incidental group). In 5 cases of the incidental group, tumors were found at a routine health examination, whereas in the remaining 26 cases tumors were found during the examination or treatment for unrelated diseases. On both the incidental group and symptomatic group, higher right-to-left side ratio was noted in the laterality of tumors detected by ultrasound scanning. The size of tumors in the incidental group was significantly larger than that in the symptomatic group, but there was no significant difference in size between the tumors detected by ultrasound and those detected by CT scan in either the symptomatic group or in the incidental group. In the symptomatic group 71 patients (95.9%) were found to have functioning tumor, where the most common diagnosis was primary aldosteronism (44 cases), and 68 of the 71 patients received adrenalectomy. While in the incidental group 12 patients (38.7%) were found to have functioning tumor, where the most common diagnosis was pheochromocytoma (7 cases), followed by Cushing's syndrome (3 cases) including one case with so-called pre-Cushing's syndrome, and all of the 12 patients received adrenalectomy. Of 16 primary incidental adrenal tumors which did not have any hormonal functions, 5 tumors larger than 30 mm in diameter were resected and the remaining 11 tumors were followed up without operation. Since the incidence of incidental adrenal tumor may increase in the future, careful diagnosis and decision of indication for surgery are required.

Adolescent↗

[Cranio-orbital zygomatic extradural approach for cavernous sinus or Meckel's cave tumors].

Direct surgery to cavernous sinus (CS) lesions has become one of the optimal treatments based on advancement in microsurgical anatomy and imaging modality, and the progress of microsurgical techniques. We have removed the CS or Meckel's cave tumors extradurally when they do not extend intradurally, using modified Al-Mefty's cranio-orbital zygomatic craniotomy. Three CS tumors; trigeminal neurofibroma, squamous cell carcinoma and chondrosarcoma, and a Meckel's cave meningioma were reported. Total removal was achieved in all but one (case 4). Postoperative complications were permanent ophthalmoplegia in one, transient ophthalmoplegia in one, subcutaneous CSF accumulation in two and trigeminal dysfunction in one. The extradural approach can be the first choice of methods for total removal of tumors when they are confined to the CS or Meckel's cave.

Adult↗

Wound healing effect of the new imidazole antimycotic lanoconazole in rats.

The wound healing effect of cream preparations of lanoconazole (CAS 101530-10-3, NND-318), an antimycotic imidazole compound, was examined using an excisional open skin-wound model produced on the back of rats. The rapid decrease in the size of wounded areas showed that 0.5% and 1% lanoconazole creams accelerated spontaneous healing. The effectiveness was almost similar to that of an ointment containing 5% deproteinized calf blood extract (DCBE), a wound healing agent on the market. In contrast, neither 1% clotrimazole cream nor 1% bifonazole cream, both of which are imidazole antimycotics, showed an accelerative effect. The wound healing effect of lanoconazole was further confirmed by histological evaluation; a thicker and more cellular granulation tissue was formed, and epidermal regeneration was more stimulated by lanoconazole than by non-treatment or vehicle alone. The effect of lanoconazole on the formation of granulation tissue in rats was also studied using a cotton pellet implantation method. Lanoconazole accelerated the formation of this tissue in terms of dry weight in a dose dependent manner (0.5-4 mg/pellet), and collagen content and angiogenesis also increased in the stimulated tissue, indicating that these accompany the compound-induced acceleration of tissue formation. These results suggest that lanoconazole has a distinctive wound healing effect which is a feature no other imidazole antimycotic is known to possess to date.

Administration, Topical↗

Wound healing effect of malotilate in rats.

The wound healing effect of malotilate (CAS 59937-28-9, NKK-105) was investigated by using an excisional skin-wound model produced on the back of normal and healing-impaired (induced by prednisolone pretreatment) rats. The rapid decrease in the square measure of wound areas and the improvement in the histological evaluation clarified that 0.3% and 1% cream preparations of malotilate were obviously effective in accelerating spontaneous healing in the normal rats. The accelerative effect of malotilate cream preparations was likely superior to that of an ointment containing 5% deproteinized calf blood extract used as a reference agent. The same effect was also observed in the healing-impaired rats. The histological findings revealed that a thicker and more cellular granulation tissue, which in turn created an adequate bed for rapid re-epithelization, was formed in the malotilate-treated animals. Acceleration of granulation tissue formation by malotilate was also supported by the cotton pellet implantation method. It is concluded from these results that malotilate seems to be a promising agent for topical wound therapy.

Administration, Topical↗

[Advances in genetic diagnostics for respiratory tract infections].

The past decade has seen the rapid advancement of molecular biology and its application in the field of infectious diseases. The polymerase chain reaction (PCR) is a technique which brings about the in vitro amplification of DNA, and is clinically useful in the sensitive, specific and rapid diagnosis of various infectious diseases. The fast diagnosis of viral infections using PCR is a prime example, since viral culture may take weeks to grow and since serologic conversion seldom occurs until the convalescent phase of the clinical illness. Similarly, PCR is applicable to the diagnosis of pulmonary infections caused by mycobacteria, Legionella, methicillin-resistant Staphylococcus aureus, anaerobes, Mycoplasma, Chlamydia, Pneumocystis carinii and so on. On the other hand, the drug-resistant phenotype of a microorganism is predictable by the detection of gene alterations related to the drug resistance. For example, the deletion of the catalase-peroxidase gene relating to isoniazid resistance of mycobacteria, and point mutations in the RNA polymerase beta subunit (rpoB) gene relating to rifampicin resistance have been elucidated. As these applied techniques become more widely available and less costly, they should contribute not only to the rapid diagnosis of infectious diseases, but also to the adequate selection of antibiotics and the shortening of hospitalization.

Bacterial Infections↗

Correlation between disease activity and arterial blood pressure in Crohn's disease.

OBJECTIVE: The aim of this study is to assess haemodynamics in patients with Crohn's disease (CD) receiving total parenteral or enteral nutrition (TPEN). METHODS: We compared changes in systemic arterial blood pressure (BP) before and after 48 courses of TPEN in 34 patients with CD and 19 courses of TPEN in 10 patients with other gastrointestinal diseases. We simultaneously measured the Crohn's disease activity index (CDAI) and biochemical parameters. RESULTS: BP increased significantly during TPEN in CD patients (after: 85.1 +/- 7.4 mmHg vs. before: 75.2 +/- 7.9 mmHg, P < 0.001). The increase in BP was negatively correlated with changes in the Crohn's disease activity index. BP decreased significantly after TPEN in patients with other diseases (P < 0.001), despite an improvement in their general condition. There was no significant difference in volume status between CD patients and patients with other diseases. CONCLUSION: These findings suggest that determination of arterial blood pressure may be useful for assessing disease severity in patients with CD and that a fall in blood pressure may contribute to disease activity.

Adult↗

Analysis of p53 gene mutations in human glioma cell lines.

Seven human glioma cell lines were examined for mutations of the p53 gene and their mRNA and protein expressions. Five cell lines revealed a missense mutation at, codons 237, 245, or 273. Their p53 mRNA expression was variably distinct and not always comparable to p53 protein expression, suggesting difference in the transcriptional and posttranscriptional regulation. One cell line had a splicing mutation in intron 9 and abnormal splicing was actually demonstrated by RT-PCR analysis. The remaining 1 cell line showed no PCR-amplification of the p53 gene sequence. In an examination of the original tumor tissues, the same mutations were demonstrated in the 5 tumors examined, strongly suggesting that the mutations in the glioma cell lines were derived from their original tumor tissues.

Brain Neoplasms↗

[Differential diagnosis of tuberculous pleurisy by the measurement of cytokine concentration in pleural effusion].

Pleural fluids obtained from 26 patients with tuberculous pleurisy (T-group), 11 with parapneumonic pleurisy (B-group) and 21 with malignant pleurisy (M-group) were tested for their biologic parameters and cytokine concentrations. 1) The average age of T-group was over 10 years lower than that of M-group with a statistically significant difference. 2) The average CRP value of B-group and the positivity on PPD skin test of T-group were higher than those of the other groups, respectively. 3) Yellowish pleural fluids were mainly observed in T- and B-group, while bloody pleural fluids were mostly seen in M-group with a statistically significant difference. The average total protein amount and adenosine deaminase value in pleural fluid significantly increased in T-group. The percentage of polymorphonuclear leukocytes showed a significant increase in B-group, while lymphocytes significantly increased in T-group with a statistically significant difference. 4) Although no significant difference in concentrations of IL-1 beta, IL-2, IFN-gamma and TNF-alpha in serum was noticed among the three groups, the average concentrations of IFN-gamma and TNF-alpha in pleural fluid in T-group were significantly higher than those in the other groups. 5) TNF-alpha-mRNA of mononuclear cells in pleural fluid was strongly expressed in 3 out of 11 patients of T-group, while no expression was observed in 6 patients of M-group. In conclusion, the measurement of concentrations of two kinds of cytokines in pleural fluid, IFN-gamma and TNF-alpha, may be clinically useful for the differential diagnosis of tuberculous pleurisy from parapneumonic pleurisy and malignant pleurisy.

Adult↗

[Clinical evaluation of sulbactam/cefoperazone for lower respiratory tract infections. Correlation between the efficacy of sulbactam/cefoperazone and beta-lactamase].

The efficacy and safety of sulbactam/cefoperazone (SBT/CPZ) were evaluated in 42 patients with respiratory tract infections, including pneumonia (29 patients) and lower respiratory tract infections (5 patients). Overall clinical efficacy rates (excellent + good) were 79% in pneumonia and 80% in respiratory tract infections in 34 patients evaluated for clinical efficacy. It was excellent that the clinical efficacy rate was 92% in mild and moderate pneumonia. Pathogens isolated from sputa were 31 strains, including 8 strains of Pseudomonas aeruginosa, 7 of Streptococcus pneumoniae, 3 of Staphylococcus aureus and 3 of Haemophilus influenzae. Since the isolates were eradicated in 18 strains, replaced in 3, unchanged in 2 and unknown in 8, the overall eradication rate was 91%. The eradication rates were 89% in beta-lactamase producing strains and 100% in beta-lactamase positive sputum, and excellent or good in 19 (83%) of 23 patients with beta-lactamase negative sputum. The eradication rate was 88% in 5 patients with beta-lactamase positive sputum. One patient experienced a moderate rash. Abnormal laboratory test values were observed in 10 patients (26.3%), but these abnormalities were mild and transient. These results suggested that SBT/CPZ was effective and safe for the treatment of respiratory tract infections caused by beta-lactamase producing as well as beta-lactamase non-producing bacteria.

Aged↗